The art of piercing with a C-shaped unit is well known and several manufacturers have quality products of this type on the market. However, these products are expensive and complicated. The piercing unit of my invention combines low cost, quality and simplicity. The C-frame is made of cast iron and the punch holder slide is made of tool steel so friction therebetween is minimized. One hole drilled from the top and part way through the bottom provides the slideway for the punch holder slide and also the receiving recess for the die sleeve, the latter being backed up by an internal shoulder formed by the bottom of the drilled hole. The punch holder slide is backed up by a shoulder adjacent to the inner end of the stripper bolt, and the punch is backed up by the inner extremity of the stripper bolt and therefore massive design to absorb the piercing force is not necessary.